[Help] Mage horrible Dps/Combustion

My guild is 12/12 and this week we will start heroics. And my percentile is complete garbage. Under 30 sometimes 25.
I am 510, Troll fire mage spent 1-2hours last night trying to a good combust. My best shot was 20k
I uploaded the video of my best combust so far on a dummy.
I do exactly what i am supposed to do:
Prepot
Mirror images
hard cast Pyro
Wait for heat up + Pyro
wait for Trinkets to proc
Use Cds(ie berserking etc)
POM
AT
Spam pyro(till done)
Rehit AT
Spam pyro(till done)
Hit combust when last pyro in the Air.

Yes what Eihwaz is saying is true, Pyro dot has no bearing on Combustion anymore, the only benefit of using your Combust after your Pyro!/PomPyro chain is that after a couple of these crit (in a row) you should be using Combustion. Since the crits are what are going to add into your ignite for nomnomnom tasty combustion. Use some sort of scrolling battle text or even just keep the default bliz UI on to just see direct damage and watch for BIG NUMBERS. 2+crits and your procs... I had a ~120k Combust on an opening pull of Durumu last week.

This is a very common misconception. You should not hit combustion when you've fired your 4 pyros, thats useless.

But you should combust when 2 (or more if you like to gamble) pyros critted in a row.

Did you read the fire mage guide in the forum ? You should find a more detailled description of how ignite works. That's a very common question here

While this might be true, if you do the pom-AT combo you most likely crit at some point. Only if you are very unlucky then you get only 4 pyros with no crit at all...on the other hand with a fucked up rng if you dont use it then you just might sit forever on your cds...

While this might be true, if you do the pom-AT combo you most likely crit at some point. Only if you are very unlucky then you get only 4 pyros with no crit at all...on the other hand with a fucked up rng if you dont use it then you just might sit forever on your cds...

There's only one case where this could be good. If your 2 (or 3 if you are really lucky) pyros crit.

If your 2 first pyro crit, your combustion will be bigger if you Combustion now compared to after the 4 pyro.
If you 2 middle pyro crit, same thing.

And you are far more likely I think to have to Combustion in the beggining, because for your first pyro you'll have Pyro! + HU procs, so most of the time you first 2 pyros dont use PoM, which result in a bigger ignite (because HU increase the damage of Pyroblast by 25% if i'm not mistaken, whereas PoM Pyro doesnt)

If you popped your presence of mind/alter time macro and those pyro's aren't critting, you definitely want to reconsider using combustion. Someone else already said it, but yes, waiting for 2 pyro crits back to back is a better bet... or at least make sure your trinkets are procced when you do that macro. To be honest, 510 is too low for fire, it may be the spec you like best, but be prepared to be on the low end of the dps meters - especially if a lot of your gear has mastery with no crit on it (most of the VP stuff is awful for fire, and the stuff that isn't ends up taking a tier slot).

I really hate how RNG dependent Fire is, it's just badly designed imo. Destro is a spec that similarly relies on crits, but imho deals with it better.

Whenever I play destro I'm having fun, with Fire I'm frustrated at least half the time because the damn crits come just after I've given up on achieving a good Ignite and used Combustion with a mediocre Ignite. Or I just don't get any damn crits at all.

A few days ago I tested on a doll a bit, I just chain-casted Pyroblast, Infernoblast when I had Heating Up, and Pyroblast! proc, nothing else, and I just didn't get any damn Combustion value higher than 20k max. With Destro, you crit, you gain an Ember, sooner or later you're guaranteed a Chaos Bolt/Shadowburn. With bad RNG with Fire you can go the entire fight without a decent Combustion.

I really hate how RNG dependent Fire is, it's just badly designed imo. Destro is a spec that similarly relies on crits, but imho deals with it better.

Whenever I play destro I'm having fun, with Fire I'm frustrated at least half the time because the damn crits come just after I've given up on achieving a good Ignite and used Combustion with a mediocre Ignite. Or I just don't get any damn crits at all.

A few days ago I tested on a doll a bit, I just chain-casted Pyroblast, Infernoblast when I had Heating Up, and Pyroblast! proc, nothing else, and I just didn't get any damn Combustion value higher than 20k max. With Destro, you crit, you gain an Ember, sooner or later you're guaranteed a Chaos Bolt/Shadowburn. With bad RNG with Fire you can go the entire fight without a decent Combustion.

You are getting shit ignites casting Pyro+IB ONLY because you are doing your rotation poorly, cast time of pyro is going to cause your ignites to diminish over the course of the cast. This is why we use Fireball as a filler, not Pyro. Seems silly to complain that your ignites are poor when you are doing the rotation poorly. If you correctly cast your rotation you will see ignite go up and in turn higher combustions.

Edit: You also didn't mention having a bomb up on the target, which would also give you your pyromaniac buff... increasing ignite more.

Like all of you guys, I've been gearing mastery for Arcane last tier and since we were progressing on end bosses heroic content I didn't want to hinder my group and play another spec. Anyway, I realize that my crit is super low, I switched to frost and i will probably keep going frost since my gear seems to put out bigger numbers until i can at least get new trinkets (Aka Brillance and hydra) and the 4 set and hopefully putting me above at least 12k crit.
Thanks for the answers tho. I appreciate it